Biophysical Journal 47: 725-729 (1985)
© 1985 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Parent, L Articles by Caillé, J P Search for Related Content PubMed PubMed Citation Articles by Parent, L Articles by Caillé, J P

Fixed charges of the heart muscle interstitium.

ABSTRACT

The interstitium of the heart muscle is primarily composed of ground substance. The glycoproteins and proteoglycans that formed the ground substance bore negative charges at neutral pH like the glycosaminoglycans and proteoglycans of the water-rich phase of the interstitium. Microelectrodes were used to look for the existence of an electrical potential between the interstitium of the rabbit papillary muscle and an ambient medium. Evidence is presented for the existence of such an electrical potential. When the ambient solution was a Krebs solution, this potential was evaluated at -5.7 mV. This electrical potential is dependent on the filling solution of the microelectrodes and on the ambient medium; in rabbit serum, the electrical potential diminished to -0.6 mV. Assuming that this potential is a measure of the Donnan potential, the Cl and Na activities in the interstitium were evaluated to 76 and 135 mM when the rabbit papillary muscle was superfused with a Kreb's solution.